call-by-value

This is similar to call-by-value mechanism used in function calls.

The Code Project Latest Articles Ajay Vijayvargiya 2010

Because of the call-by-value nature of the languages we're talking about, the expression used for the source parameter will be fully evaluated (not the same as enumerated!) before Let gets called, so we can feed it (again in a call-by-value manner) to the function which then can refer to it multiple times by means of its lambda expression parameter (in the sample above this is "xrs").

B# .NET Technical Community Homepage bart 2010

With this keyword, we put all by-value captured variables into call-by-value mode.

The Code Project Latest Articles Ajay Vijayvargiya 2010

Because of the call-by-value nature of the languages we're talking about, the expression used for the source parameter will be fully evaluated (not the same as enumerated!) before Let gets called, so we can feed it (again in a call-by-value manner) to the function which then can refer to it multiple times by means of its lambda expression parameter (in the sample above this is "xrs").

B# .NET Technical Community Homepage bart 2010

For that very reason, side-effect permitting languages have a much harder time carrying out optimizations to code and need to be very strict about specifying the order in which operations are performed (e.g. in C#, arguments to a method call - which is always "call-by-value" - are evaluated in a left-to-right order).

B# .NET Technical Community Homepage bart 2010

We will look into last one - capturing in call-by-value mode.

The Code Project Latest Articles Ajay Vijayvargiya 2010

I assume that you know that call-by-value, by reference and by constant reference mean.

The Code Project Latest Articles Ajay Vijayvargiya 2010

For that very reason, side-effect permitting languages have a much harder time carrying out optimizations to code and need to be very strict about specifying the order in which operations are performed (e.g. in C#, arguments to a method call - which is always "call-by-value" - are evaluated in a left-to-right order).

B# .NET Technical Community Homepage bart 2010

We said at the beginning that the reason we cannot use functions and methods to represent everything we can write in code is because Ruby uses call-by-value to pass parameters to functions.

raganwald 2009

This technique gets us almost all of what we want for this common case of wanting to work around call-by-value semantics.

raganwald 2009